/*
Copyleft (C) 2005 H�lio Perroni Filho
xperroni@yahoo.com
ICQ: 2490863

This file is part of ChatterBean.

ChatterBean is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

ChatterBean is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with ChatterBean (look at the Documents/ directory); if not, either write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA, or visit (http://www.gnu.org/licenses/gpl.txt).
 */

package bitoflife.chatterbean.aiml;

import org.xml.sax.Attributes;

import bitoflife.chatterbean.AliceBot;
import bitoflife.chatterbean.Context;
import bitoflife.chatterbean.Match;
import bitoflife.chatterbean.script.Interpreter;

public class System extends TemplateElement {
	/*
	 * Constructors
	 */

	public System(Attributes attributes) {
	}

	public System(Object... children) {
		super(children);
	}

	/*
	 * Methods
	 */

	public String process(Match match) // 这个函数很重要
	{
		try {
			AliceBot bot = match.getCallback();
			Context context = bot.getContext();
			Interpreter interpreter = (Interpreter) context
					.property("beanshell.interpreter");
			if (interpreter == null)
				return "";

			String script = super.process(match);
			interpreter.variable("result", null);
			interpreter.variable("match", match);

			Object evaluated = interpreter.evaluate(script);
			Object result = interpreter.variable("result");
			if (result == null)
				result = evaluated;

			interpreter.variable("match", null);

			return (result != null ? result.toString() : "");
		} catch (Exception e) {
			throw new RuntimeException("Evaluation error on <system> tag", e);
		}
	}
}
